Frost dates for 78240 — San Antonio, TX
How San Antonio compares
- In 8 years out of 10, the last spring frost in San Antonio falls between January 29 and March 17, a 47-day window. The first fall frost falls between November 7 and December 22.
- The median last frost is 17 days earlier than the Texas median of Mar 15.
- Its 275-day growing season is longer than 84% of the 1,316 Texas places with a regular frost season (state median 245 days).
- The last frost is 5 days earlier than the zone 9a median of Mar 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 9a chart.
- The weather station records an average of 14 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | January 29 |
| 50% (median) | February 26 |
| 10% (safe for tender plants) | March 17 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | November 7 |
| 50% (median) | November 28 |
| 90% (late) | December 22 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for San Antonio, TX
Frost dates for 78240 — San Antonio, TX — last frost Feb 26, first frost Nov 28, zone 9a. whenisthelastfrost.com
When to plant vegetables in San Antonio, TX
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Dec 4 – Dec 18 | Jan 29 – Feb 12 | — | — |
| Peppers | Dec 18 – Jan 1 | Mar 12 – Mar 26 | — | — |
| Eggplant | Dec 18 – Jan 1 | Mar 12 – Mar 26 | — | — |
| Tomatoes | Jan 1 – Jan 15 | Mar 5 – Mar 19 | — | — |
| Lettuce | Jan 1 – Jan 15 | Feb 5 – Feb 19 | Jan 29 – Mar 5 | Oct 3 – Oct 31 |
| Kale | Jan 1 – Jan 15 | Jan 29 – Feb 12 | Jan 29 – Feb 12 | Sep 19 – Oct 10 |
| Broccoli | Jan 1 – Jan 15 | Feb 12 – Feb 26 | — | Aug 22 – Sep 12 |
| Cabbage | Jan 1 – Jan 15 | Feb 5 – Feb 19 | — | Aug 22 – Sep 12 |
| Cauliflower | Jan 1 – Jan 15 | Feb 12 – Feb 26 | — | Aug 22 – Sep 12 |
| Okra | Jan 15 – Jan 29 | Mar 19 – Apr 2 | Mar 19 – Apr 2 | — |
| Basil | Jan 15 – Jan 29 | Mar 5 – Mar 19 | — | — |
| Peas | — | — | Jan 15 – Feb 5 | Sep 5 – Sep 26 |
| Spinach | — | — | Jan 15 – Feb 5 | Oct 3 – Oct 24 |
| Radishes | — | — | Jan 22 – Mar 5 | Oct 17 – Nov 7 |
| Cucumbers | Jan 29 – Feb 5 | Mar 12 – Mar 19 | Mar 5 – Mar 19 | Sep 12 – Sep 26 |
| Zucchini & Summer Squash | Jan 29 – Feb 5 | — | Mar 5 – Mar 19 | Sep 19 – Oct 3 |
| Winter Squash & Pumpkins | Jan 29 – Feb 5 | — | Mar 5 – Mar 19 | — |
| Melons & Watermelon | Jan 29 – Feb 5 | Mar 12 – Mar 26 | — | — |
| Carrots | — | — | Feb 5 – Mar 5 | Sep 5 – Sep 19 |
| Beets | — | — | Feb 5 – Mar 5 | Sep 19 – Oct 3 |
| Potatoes | — | — | Feb 5 – Feb 26 | — |
| Swiss Chard | — | — | Feb 12 – Mar 12 | Sep 19 – Oct 3 |
| Cilantro | — | — | Feb 12 – Mar 5 | Oct 3 – Oct 24 |
| Green Beans | — | — | Mar 5 – Mar 26 | Sep 12 – Sep 26 |
| Sweet Corn | — | — | Mar 5 – Mar 19 | — |
| Sweet Potatoes | — | Mar 12 – Apr 2 | — | — |
| Garlic | — | — | — | Nov 14 – Dec 19 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the San Antonio Intl Ap, TX weather station, 12 km away (elevation 791 ft (241 m)).
ZIP codes in San Antonio: 78201 78202 78203 78204 78205 78206 78207 78208 78209 78210 78211 78212 78213 78214 78215 78216 78217 78218 78219 78220 78221 78222 78223 78224 78225 78226 78227 78228 78229 78230 78231 78232 78233 78235 78237 78238 78239 78240 78241 78242 78243 78244 78245 78246 78247 78248 78249 78250 78251 78252 78253 78254 78255 78256 78257 78258 78259 78260 78261 78263 …
Frost dates near San Antonio
- Jbsa Ft Sam Houston Feb 25 · Nov 28
- Jbsa Lackland Feb 25 · Nov 28
- Helotes Mar 15 · Nov 13
- Macdona Feb 22 · Dec 2
- Rio Medina Feb 18 · Dec 9
- Converse Feb 21 · Dec 5
- Von Ormy Feb 22 · Dec 2
- Universal City Feb 21 · Dec 5
Frequently asked questions
When is the last frost in San Antonio, TX?
The median last spring frost in San Antonio, TX is February 26. There is still about a 10% chance of frost after March 17, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in San Antonio, TX?
The median first fall frost is November 28, with about a 10% chance of frost before November 7.
How long is the growing season in San Antonio, TX?
About 275 days between the median last spring frost and first fall frost.
What planting zone is San Antonio, TX?
San Antonio, TX is in USDA hardiness zone 9a.